An apparatus and method for cooling semiconductor devices. A cooling system for semiconductor devices is disclosed and includes a semiconductor substrate, horizontal channels and a cooling medium. Specifically, the semiconductor substrate is incorporated into a die. Also, one or more horizontal channels are formed in a backside of the semiconductor substrate of the die. The horizontal channels collect thermal energy that is generated by electrical components located on a front side of the semiconductor substrate. A cooling medium circulates within the one or more horizontal channels for transferring the thermal energy away from the die.